/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

\*---------------------------------------------------------------------------*/

#include "ListOps.H"

// * * * * * * * * * * * * * * * Global Functions  * * * * * * * * * * * * * //

Foam::labelList Foam::invert
(
	const label len,
	const UList<label>& map
)
{
	labelList inverse(len, -1);

	forAll(map, i)
	{
		label newPos = map[i];

		if (newPos >= 0)
		{
			if (inverse[newPos] >= 0)
			{
				FatalErrorIn("invert(const label, const UList<label>&)")
					<< "Map is not one-to-one. At index " << i
					<< " element " << newPos << " has already occurred before"
					<< nl << "Please use invertOneToMany instead"
					<< abort(FatalError);
			}

			inverse[newPos] = i;
		}
	}
	return inverse;
}


Foam::labelListList Foam::invertOneToMany
(
	const label len,
	const UList<label>& map
)
{
	labelList nElems(len, 0);

	forAll(map, i)
	{
		if (map[i] >= 0)
		{
			nElems[map[i]]++;
		}
	}

	labelListList inverse(len);

	forAll(nElems, i)
	{
		inverse[i].setSize(nElems[i]);
		nElems[i] = 0;
	}

	forAll(map, i)
	{
		label newI = map[i];

		if (newI >= 0)
		{
			inverse[newI][nElems[newI]++] = i;
		}
	}

	return inverse;
}


Foam::labelList Foam::identity(const label len)
{
	labelList map(len);

	forAll(map, i)
	{
		map[i] = i;
	}
	return map;
}


// ************************************************************************* //
